Abstract / Description of output
Solid hydrogen is expected to become a monatomic metal under sufficiently high
compression. With hydrogen having only a single valence electron and no ion core, the nature of x-ray diffraction patterns from the electron gas of monatomic metallic hydrogen is uncertain, and it is unclear whether they may yield enough information for a crystal structure determination. With emphasis on the Cs-IV-type (I41/amd) structure predicted for hydrogen at ∼500 GPa, the electron density distributions, zero-point and thermal atomic motion, and x-ray diffraction intensities are determined from first-principles calculations for several candidate phases of metallic hydrogen. It is shown that the electron distribution is much more structured than might be expected from the commonly employed free-electron-gas picture, and in fact more modulated
than what is obtained from the superposition of free-atom charge densities. We demonstrate that an identification of the crystal structure of monatomic metallic hydrogen from x-ray diffraction is fundamentally possible and discuss the possibility of single-crystal diffraction from metallic hydrogen. An atomic scattering factor for the hydrogen atom in monatomic metallic hydrogen is
constructed to aid the quantitative analysis of diffraction intensities from future x-ray diffraction experiments.
compression. With hydrogen having only a single valence electron and no ion core, the nature of x-ray diffraction patterns from the electron gas of monatomic metallic hydrogen is uncertain, and it is unclear whether they may yield enough information for a crystal structure determination. With emphasis on the Cs-IV-type (I41/amd) structure predicted for hydrogen at ∼500 GPa, the electron density distributions, zero-point and thermal atomic motion, and x-ray diffraction intensities are determined from first-principles calculations for several candidate phases of metallic hydrogen. It is shown that the electron distribution is much more structured than might be expected from the commonly employed free-electron-gas picture, and in fact more modulated
than what is obtained from the superposition of free-atom charge densities. We demonstrate that an identification of the crystal structure of monatomic metallic hydrogen from x-ray diffraction is fundamentally possible and discuss the possibility of single-crystal diffraction from metallic hydrogen. An atomic scattering factor for the hydrogen atom in monatomic metallic hydrogen is
constructed to aid the quantitative analysis of diffraction intensities from future x-ray diffraction experiments.
Original language | English |
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Article number | 185401 |
Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | Journal of Physics: Condensed Matter |
Volume | 36 |
Issue number | 18 |
DOIs | |
Publication status | Published - 7 Feb 2024 |
Keywords / Materials (for Non-textual outputs)
- high pressure
- metallic hydrogen
- x-ray diffraction
- density functional theory
- lattice dynamics
- atomic scattering factor